I wrote my email to have the Shift account, but I think I made a mistake when I wrote it and now I do not receive any code.
Nor does it allow me to send another email to send me a new code, just ask me for the one that has already been sent to me supposedly.

I’m assuming you’re posting in the HC:XB1 section because you’re trying to get the Golden Key reward for creating the SHiFT account for Borderlands 2?

You’ll need to have your SHiFT account linked to your XBL account for that to happen. Did you create the account through the website or through the in-game menu? If the former, you should be able to link the account through the page I mentioned.

In terms of response to the support ticket, you should get an automatic reply fairly quickly, and then a personal response within 24 hours - the actual time varies depending on how busy the system is.

Edit: this link describes the process for creating the SHiFT account through the in-game menu - is this what you did?